1. Field of the Invention
This invention pertains to the control of energy consumption in an electrostatic precipitator.
More particularly, this invention pertains to method and apparatus for continuously and automatically regulating electric power supplied to the corona generating electrodes of an electrostatic precipitator in response to changes in opacity of the flue gas exiting from the precipitator.
2. State of the Art
Control circuitry illustrative of the prior art for energizing the corona generating electrodes of an electrostatic precipitator is described in U.S. Pat. No. 3,745,749. A more recent automatic voltage control system for energizing the corona generating electrodes of an electrostatic precipitator is described in copending U.S. patent application Ser. No. 06/041,965 filed on May 23, 1979, which application is owned by the assignee of the present application.
It has been customary for the corona generating electrodes of an electrostatic precipitator to be powered at the highest voltage practicable in order to achieve maximum electric field strength between the corona generating electrodes and the particulate collecting electrodes. Power control techniques for electrostatic precipitators have heretofore been primarily concerned with providing rapid response to sparking conditions, so that power can be shut OFF or reduced below sparking potential promptly after the occurrence of a spark, and reapplied (preferably in a "fast ramp" manner to reach a predetermined level below a selected voltage control value) in a matter of milliseconds after the spark has occurred.
In the prior art, power control techniques for electrostatic precipitators have not been used primarily to control energy consumption. Accordingly, no technique has heretofore been developed for continuously and automatically varying the voltage applied to the corona generating electrodes of an electrostatic precipitator in order to minimize the electric power consumed in removing particulates from the gas stream passing through the precipitator.